Method of making an edge fold having substantially uniform gathers for absorbent article

ABSTRACT

A method for making an edge fold on an absorbent article having longitudinal edges including the steps of activating a portion of an absorbent article along its longitudinal edges to create substantially uniform gathers, folding a portion of the absorbent article along its longitudinal edges, and bonding a portion of the absorbent article along its longitudinal edges. Said method may include the step of cutting a portion of the absorbent article before the step of folding. Said method may include the step of cutting a portion of the absorbent article after the step of bonding. Said step of activation may include the application of heat to the absorbent article to assist in the activating process, whether before or during activation. Said bonding may be performed by application of adhesive, ultrasonic bonding, compression bonding, thermal bonding, radio frequency bonding, infrared bonding and combinations thereof. Absorbent articles include disposable diapers, sanitary napkins, pantiliners, incontinence briefs, and incontinence undergarments. Said step of folding creates an edge fold that substantially covers a portion of a longitudinal edge between a pair of side panels.

FIELD OF THE INVENTION

This invention relates to edge folds on absorbent articles, and moreparticularly to edge folds having substantially uniform gathers ondisposable absorbent articles, such as diapers.

BACKGROUND OF THE INVENTION

Infants and other incontinent individuals wear disposable absorbentarticles such as diapers to receive and contain urine and other bodyexudates. Absorbent articles function both to contain the dischargedmaterials and to isolate these materials from the body of the wearer andfrom the wearer's garments and bed clothing. Disposable absorbentarticles having many different basic designs are known to the art.

A typical absorbent article has a chassis that includes a liquidpervious topsheet, and a liquid impervious backsheet joined to thetopsheet. An absorbent core is typically positioned between the topsheetand the backsheet. The chassis has a generally elongated shape, whichcan be rectangular or hourglass shaped. The long dimension of thechassis defines two opposed edges referred to as the longitudinal edges.A portion of each longitudinal edge defines the leg opening of thediaper when worn.

To better contain body exudates, absorbent articles often haveelasticized leg openings, referred to as leg cuffs that are designed tofit snugly about the legs of the wearer. Leg cuffs can be made by simplyplacing tensioned elastic strands along the longitudinal edges, forexample. When contracted the elastic strands form gathers of material.Leg cuffs, as opposed to barrier cuffs that are generally disposedinboard, that is, toward the center of the diaper and away from thelongitudinal edges of the diaper chassis, can include a portion of thelongitudinal edge of the diaper chassis. This longitudinal edge is oftenunsightly, that is, it appears as an unfinished edge that may have arather rough appearance. The appearance is important, as consumerperception of softness and comfort are significant considerations forcommercial success in the disposable absorbent article field.

It would be desirable to have a disposable absorbent article having aleg cuff that has a finished, comfortable appearance.

Additionally, it would be desirable to have a method for making a legcuff having a finished appearance in a commercially viable manner.

Further, it would be desirable to have a disposable absorbent articlewith a leg cuff having a finished appearance, with the finishedappearance limited to the portion of the longitudinal edge of thechassis that defines a leg opening when worn. Said finished appearancebeing formed by an edge fold having substantially uniform gathers.

Finally, it would be desirable to have a commercially-viable method ofmaking a disposable absorbent article with a leg cuff having a finishedappearance, with the finished appearance limited to the portion of thelongitudinal edge of the chassis that defines a leg opening when worn.Said finished appearance being formed by an edge fold havingsubstantially uniform gathers.

BRIEF SUMMARY OF THE INVENTION

A method for making an edge fold on an absorbent article havinglongitudinal edges including the steps of activating a portion of anabsorbent article along its longitudinal edges to create substantiallyuniform gathers, folding a portion of the absorbent article along itslongitudinal edges, and bonding a portion of the absorbent article alongits longitudinal edges. Said method may include the step of cutting aportion of the absorbent article before the step of folding. Said methodmay include the step of cutting a portion of the absorbent article afterthe step of bonding. Said step of activation may include the applicationof heat to the absorbent article to assist in the activating process,whether before or during activation. Said bonding may be performed byapplication of adhesive, ultrasonic bonding, compression bonding,thermal bonding, radio frequency bonding, infrared bonding andcombinations thereof. Absorbent articles include disposable diapers,sanitary napkins, pantiliners, incontinence briefs, and incontinenceundergarments. Said step of folding creates an edge fold thatsubstantially covers a portion of a longitudinal edge between a pair ofside panels.

A disposable diaper having a topsheet, a backsheet, an absorbent coredisposed between said topsheet and said backsheet, said topsheet andsaid backsheet defining a periphery and longitudinal edges, portions ofsaid longitudinal edges defining leg openings when said disposablediaper is worn and at least one edge fold along said portions of saidlongitudinal edges.

All patents, articles, documents, and other materials cited are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention.

All measurements are in SI units, unless otherwise specified.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims pointing out anddistinctly claiming the present invention, it is believed the same willbe better understood by the following drawings taken in conjunction withthe accompanying specification wherein like components are given thesame reference number.

FIG. 1 is a perspective view of a general embodiment of an absorbentarticle of the present invention;

FIG. 2 is a bottom view of a first embodiment of an absorbent article ofthe present invention;

FIG. 3 is a bottom view of a second embodiment of an absorbent articleof the present invention;

FIG. 4 is a bottom view of a third embodiment of an absorbent article ofthe present invention;

FIG. 5 is a bottom view of a fourth embodiment of an absorbent articleof the present invention;

FIG. 6 is a bottom view of a fifth embodiment of an absorbent article ofthe present invention;

FIG. 7 is a bottom view of a sixth embodiment of an absorbent article ofthe present invention;

FIG. 8 is a bottom view of a seventh embodiment of an absorbent articleof the present invention;

FIG. 2 a is a bottom view of the first embodiment in FIG. 2 after beingprocessed by the manufacturing step of activation;

FIG. 3 a is a bottom view of the second embodiment in FIG. 3 after beingprocessed by the manufacturing step of activation;

FIG. 4 a is a bottom view of the third embodiment in FIG. 4 after beingprocessed by the manufacturing step of activation;

FIG. 5 a is a bottom view of the fourth embodiment in FIG. 5 after beingprocessed by the manufacturing step of activation;

FIG. 6 a is a bottom view of the fifth embodiment in FIG. 6 after beingprocessed by the manufacturing step of activation;

FIG. 7 a is a bottom view of the sixth embodiment in FIG. 7 after beingprocessed by the manufacturing step of activation;

FIG. 8 a is a bottom view of the seventh embodiment in FIG. 8 afterbeing processed by the manufacturing step of activation;

FIG. 4 b is a bottom view of the third embodiment in FIG. 4 after beingprocessed by the manufacturing step of cutting;

FIG. 6 b is a bottom view of the fifth embodiment in FIG. 6 after beingprocessed by the manufacturing step of cutting;

FIG. 7 b is a bottom view of the sixth embodiment in FIG. 7 after beingprocessed by the manufacturing step of cutting;

FIG. 8 b is a bottom view of the seventh embodiment in FIG. 8 afterbeing processed by the manufacturing step of cutting;

FIG. 2 c is a bottom view of the first embodiment in FIG. 2 after beingprocessed by the manufacturing step of folding;

FIG. 3 c is a bottom view of the second embodiment in FIG. 3 after beingprocessed by the manufacturing step of folding;

FIG. 4 c is a bottom view of the third embodiment in FIG. 4 after beingprocessed by the manufacturing step of folding;

FIG. 5 c is a bottom view of the fourth embodiment in FIG. 5 after beingprocessed by the manufacturing step of folding;

FIG. 6 c is a bottom view of the fifth embodiment in FIG. 6 after beingprocessed by the manufacturing step of folding;

FIG. 7 c is a bottom view of the sixth embodiment in FIG. 7 after beingprocessed by the manufacturing step of folding;

FIG. 8 c is a bottom view of the seventh embodiment in FIG. 8 afterbeing processed by the manufacturing step of folding;

FIG. 2 d is a bottom view of the first embodiment in FIG. 2 after beingprocessed by the manufacturing step of bonding;

FIG. 3 d is a bottom view of the second embodiment in FIG. 3 after beingprocessed by the manufacturing step of bonding;

FIG. 4 d is a bottom view of the third embodiment in FIG. 4 after beingprocessed by the manufacturing step of bonding;

FIG. 5 d is a bottom view of the fourth embodiment in FIG. 5 after beingprocessed by the manufacturing step of bonding;

FIG. 6 d is a bottom view of the fifth embodiment in FIG. 6 after beingprocessed by the manufacturing step of bonding;

FIG. 7 d is a bottom view of the sixth embodiment in FIG. 7 after beingprocessed by the manufacturing step of bonding;

FIG. 8 d is a bottom view of the seventh embodiment in FIG. 8 afterbeing processed by the manufacturing step of bonding;

FIG. 9 shows a first exemplary embodiment of an activation apparatusthat is capable of performing the manufacturing step of activation;

FIG. 10 shows a second exemplary embodiment of an activation apparatusthat is capable of performing the manufacturing step of activation;

FIG. 11 shows an exemplary embodiment of a segment of a first rollhaving teeth that may be used in the apparatus of FIGS. 9 and 10;

FIG. 12 a shows an exemplary embodiment of a folding apparatus that iscapable of performing said folding process;

FIG. 12 b shows an exemplary embodiment of a flipping mechanismcontained in the folding apparatus of FIG. 12 a;

FIGS. 13 a-c show a progression of the folding step, wherein, FIG. 13 ashows the longitudinal edge being held by folding portion in apre-folded state, FIG. 13 b shows the folding portion folding thelongitudinal edge to create an edge fold 60, FIG. 13 c shows the foldingportion releasing the newly-formed edge fold;

FIG. 14 shows an adaptation to the folding apparatus, wherein, thefolding portion of FIGS. 13 a-c are replaced with a curved foldingmember;

FIG. 15 a shows a schematic view of an exemplary edge fold which isfolded onto the topsheet;

FIG. 15 b shows a schematic view of an exemplary edge fold which isfolded onto the backsheet;

FIG. 15 c shows a schematic view of an exemplary edge fold which isfolded onto the barrier leg cuff; this example being a multi-piecechassis;

FIG. 15 d shows a schematic view of an exemplary edge fold which isfolded onto the barrier leg cuff; this example being a uni-body chassis;

FIG. 15 e shows a schematic view of an exemplary edge fold, wherein, thebacksheet is folded onto itself as an inside fold; this example being amulti-piece chassis;

FIG. 15 f shows a schematic view of an exemplary edge fold, wherein, thebacksheet is folded onto itself as an outside fold; this example being auni-body chassis;

FIG. 16 shows a schematic view of the folding manufacturing process formaking the embodiment of FIG. 2;

FIG. 17 shows a schematic view of the folding manufacturing process formaking the embodiments of FIGS. 3 and 5; and

FIG. 18 shows a schematic view of the folding manufacturing process formaking the embodiments of FIGS. 4 and 6-8.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term “absorbent article” refers to devices thatabsorb and contain body exudates, and more specifically, refers todevices that are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. Absorbent articles include, but are not limited to, disposablediapers, sanitary napkins, pantiliners, incontinence briefs, andincontinence undergarments. The term “disposable” is used herein todescribe absorbent articles that generally are not intended to belaundered or otherwise restored or reused as an absorbent article (i.e.,they are intended to be discarded after a single use).

As used herein, the term “disposed” is used to mean that an element(s)of the diaper is formed (joined and positioned) in a particular place orposition as a unitary structure with other elements of the diaper or asa separate element joined to another element of the diaper. As usedherein, the term “joined” encompasses configurations whereby an elementis directly secured to another element by affixing the element directlyto the other element, and configurations whereby an element isindirectly secured to another element by affixing the element tointermediate member(s) that in turn are affixed to the other element.

As used herein, the term “elastic” or “elastomeric” refers to anymaterial which, upon application of a biasing force, is stretchable,that is, elongatable, at least about 60 percent (i.e., to a stretched,biased length, which is at least about 160 percent of its relaxedunbiased length), and which, will recover at least 55 percent of itselongation upon release of the stretching, elongation force. Ahypothetical example would be a one (1.0) cm sample of a material whichis elongatable to at least 1.60 cm, and which, upon being elongated to1.60 cm and released, will recover to a length of not more than 1.27 cm.Many elastic materials may be elongated by more than 60 percent (i.e.,much more than 160 percent of their relaxed length), for example,elongated 100 percent or more, and many of these materials will recoverto substantially their initial relaxed length, for example, to within105 percent of their initial relaxed length, upon release of the stretchforce. Such materials are referred to herein as “highly elastic”.

As used herein, the term “nonelastic” refers to any material that doesnot fall within the definition of “elastic” (or “elastomeric”) or“highly elastic” above.

As used herein, the term “extensible” refers to any material that, uponapplication of a biasing force, is elongatable, at least about 50%without offering a significant resistance force (less than 10 g/cm) orexperiencing catastrophic failure. Catastrophic failure includessubstantial tearing, fracturing, rupturing, or other failure in tensionsuch that, if tested in a standard tensile tester, the failure wouldresult in a sudden significant reduction in measured tensile force. Asused herein, the term “highly extensible” refers to any material which,upon application of a biasing force, is elongatable, at least about 70%,more preferably at least about 100%, and even more preferably about 120%without offering a significant resistance force (less than 10 g/cm) orexperiencing catastrophic failure.

As used herein, the term “diaper” refers to an absorbent articlegenerally worn by infants and incontinent persons about the lower torso,and includes both tape-type diapers (diapers having adhesive tapes, hookand loop fasteners, and the like, that fastened about the waist of thewearer), and pull-on pant-type diapers.

As used herein, the term “multi-piece chassis” refers to a chassishaving attached side panels. In contrast, the term “uni-body chassis”refers to a chassis having integral side panels and having a final shapedetermined by a side notch cut.

FIG. 1 is a plan view of the diaper 20 of the present invention in aflat-out state with portions of the structure being cut away to moreclearly show the construction of the diaper 20. The portion of thediaper 20 that faces the wearer is oriented towards the viewer. As shownin FIG. 1, the diaper 20 preferably comprises a liquid pervious topsheet24; a liquid impervious backsheet 26, an absorbent core 28 which ispreferably positioned between at least a portion of the topsheet 24 andthe backsheet 26; side panels 30; elasticized leg cuffs 32; and anelastic waist feature 34.

Diaper 20 is shown in FIG. 1 to have a first waist region 36, a secondwaist region 38 opposed to the first waist region 36 and a crotch region37 located between the first waist region and the second waist region38. Crotch region 37 preferably being narrower than first waist region36 and second waist region 38. The periphery of the diaper 20 is definedby the outer edges of the diaper 20 in which the longitudinal edges 50are oriented generally parallel to the longitudinal centerline 70 of thediaper 20 and the end edges 52 run between the longitudinal edges 50generally parallel to the transverse centerline 72 of the diaper 20.However, for better fit, longitudinal edges 50 are preferably curved toproduce an “hourglass” shape diaper when viewed in the flat-outconfiguration of FIG. 1. The chassis 22 of the diaper 20 comprises themain body of the diaper 20. The chassis 22 comprises at least thetopsheet 24 and the backsheet 26.

For tape-type diapers, that is, diapers intended to be fastened aboutthe wearer by use of an adhesive tape or releasable mechanical fastener,the diaper 20 can have a fastening system generally designated 40, as iscommonly known in the art. Once fastened upon the wearer, portions oflongitudinal edge 50 define leg openings 25. For pant-type diapers,first waist region 36 is joined by suitable means to the second waistregion 38, as is commonly known in the art, to make a pant-type garmenthaving leg openings 25 defined by the nonjoined portions of longitudinaledges 50. Joining of the waist regions can be accomplished byapplication of adhesive, ultrasonic bonding, compression bonding,thermal bonding, combinations thereof, and any other suitable bondingmeans known in the art which is appropriate for the specific materialsemployed.

While the topsheet 24, the backsheet 26, and the absorbent core 28 maybe assembled in a variety of well-known configurations, preferredtape-diaper configurations are described generally in U.S. Pat. No.3,860,003 entitled “Contractible Side Portions for Disposable Diaper”which issued to Kenneth B. Buell on Jan. 14, 1975; U.S. Pat. No.5,151,092 issued to Buell on Sep. 9, 1992; and U.S. Pat. No. 5,221,274issued to Buell on Jun. 22, 1993; and U.S. Pat. No. 5,554,145 entitled“Absorbent Article With Multiple Zone Structural Elastic-Like Film WebExtensible Waist Feature” which issued to Roe et al. on Sep. 10, 1996;U.S. Pat. No. 5,569,234 entitled “Disposable Pull-On Pant” which issuedto Buell et al. on Oct. 29, 1996; and U.S. Pat. No. 5,580,411 entitled“Zero Scrap Method For Manufacturing Side Panels For Absorbent Articles”which issued to Nease et al. on Dec. 3, 1996. Preferred pant-typediapers and methods for making suitable side seams are disclosed in U.S.Pat. No. 5,569,234 issued to Buell, et al. on Oct. 29, 1996, U.S. Pat.No. 5,607,537 issued to Johnson et al. on Mar. 4, 1997, U.S. Pat. No.5,662,638 issued to Johnson et al. on Sep. 2, 1997, and U.S. Pat. No.5,685,874 issued to Buell et al. on Nov. 11, 1997. Preferable seams aredisclosed in European Patent Application No. 96118654.1 titled “ThermalJoining of Webs” filed on Nov. 21, 1996 (Christoph J. Schmitz).

The backsheet 26 is generally that portion of the diaper 20 positionedadjacent the garment facing surface 45 of the absorbent core 28 whichprevents the exudates absorbed and contained therein from soilingarticles which may contact the diaper 20, such as bed sheets andundergarments. In preferred embodiments, the backsheet 26 is imperviousto liquids (e.g., urine) and comprises a thin plastic film such as athermoplastic film having a thickness of about 0.012 mm (0.5 mil) toabout 0.051 mm (2.0 mils). Suitable backsheet films include thosemanufactured by Tredegar Industries Inc. of Terre Haute, Ind. and soldunder the trade names XI 5306,X10962 and X10964. Other suitablebacksheet materials may include breathable materials that permit vaporsto escape from the diaper 20 while still preventing exudates frompassing through the backsheet 26. Exemplary breathable materials mayinclude materials such as woven webs, nonwoven webs, composite materialssuch as film-coated nonwoven webs, and micro porous films such asmanufactured by Mitsui Toatsu Co., of Japan under the designation ESPOIRNO and by EXXON Chemical Co., of Bay City, Tex., under the designationEXXAIRE. Suitable breathable composite materials comprising polymerblends are available from Clopay Corporation, Cincinnati, Ohio under thename HYTREL® blend P18-3097. Such breathable composite materials aredescribed in greater detail in PCT Application No. WO 95/16746,published on Jun. 22, 1995 in the name of E. I. DuPont and copendingU.S. patent application Ser. No. 08/744,487, filed on Nov. 6, 1996 inthe name of Curro. Other breathable backsheets including nonwoven websand apertured formed films are described in U.S. Pat. No. 5,571,096issued to Dobrin et al. on Nov. 5, 1996.

The backsheet 26, or any portion thereof, may be elastically extensiblein one or more directions. In one embodiment, the backsheet 26 maycomprise a structural elastic-like film (“SELF”) web. A structuralelastic-like film web is an extensible material that exhibits anelastic-like behavior in the direction of elongation without the use ofadded elastic materials. SELF webs suitable for the present inventionare more completely described in U.S. Pat. No. 5,518,801 entitled WebMaterials Exhibiting Elastic-Like Behavior, which issued to Chappell, etal. on May 21, 1996.

The backsheet 26 may be joined to the topsheet 24, the absorbent core 28or any other element of the diaper 20 by any attachment means known inthe art. For example, hot melt adhesives applied about the portions ofthe peripheral edges can be sufficient to join the topsheet andbacksheet to one another.

The topsheet 24 is preferably positioned adjacent the body surface 47 ofthe absorbent core 28 and may be joined thereto and/or to the backsheet26 by any attachment means known in the art. The topsheet 24 ispreferably compliant, soft feeling, and non-irritating to the wearer'sskin. Further, at least a portion of the topsheet 24 is liquid pervious,permitting liquid to readily penetrate through its thickness. A suitabletopsheet 24 may be manufactured from a wide range of materials, such asporous foams; reticulated foams; apertured plastic films; or woven ornonwoven webs of natural fibers (e.g., wood or cotton fibers), syntheticfibers (e.g., polyester or polypropylene fibers), or a combination ofnatural and synthetic fibers.

Any portion of the topsheet 24 may be coated with a lotion as is knownin the art. Examples of suitable lotions include those described in U.S.Pat. Nos. 5,607,760 entitled “Disposable Absorbent Article Having ALotioned Topsheet Containing an Emollient and a Polyol PolyesterImmobilizing Agent” which issued to Roe on Mar. 4, 1997; U.S. Pat. No.5,609,587 entitled “Diaper Having A Lotion Topsheet Comprising A LiquidPolyol Polyester Emollient And An Immobilizing Agent” which issued toRoe on Mar. 11, 1997; U.S. Pat. No. 5,635,191 entitled “Diaper Having ALotioned Topsheet Containing A Polysiloxane Emollient” which issued toRoe et al. on Jun. 3, 1997; and U.S. Pat. No. 5,643,588 entitled “DiaperHaving A Lotioned Topsheet” which issued to Roe et al. on Jul. 1, 1997.

The absorbent core 28 may comprise any absorbent material which isgenerally compressible, conformable, non-irritating to the wearer'sskin, and capable of absorbing and retaining liquids such as urine andother certain body exudates. The absorbent core 28 may be manufacturedin a wide variety of sizes and shapes (e.g., rectangular, hourglass,“T”-shaped, asymmetric, etc.) and may comprise a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as comminuted wood pulp, which is generallyreferred to as airfelt. Examples of other suitable absorbent materialsinclude creped cellulose wadding; melt-blown polymers, including coform;chemically stiffened, modified or cross-linked cellulosic fibers;tissue, including tissue wraps and tissue laminates; absorbent foams;absorbent sponges; superabsorbent polymers; absorbent gelling materials;or any other known absorbent material or combinations of materials.

The diaper 20 can also comprise at least one elastic waist feature 34that helps to provide improved fit and containment. The elastic waistfeature 34 is generally intended to elastically expand and contract todynamically fit the wearer's waist. The elastic waist feature 34preferably extends at least longitudinally outwardly from at least onewaist edge 62 of the absorbent core 28 and generally forms at least aportion of the end edge 52 of the diaper 20. Disposable diapers areoften constructed so as to have two elastic waist features, onepositioned in the first waist region 36 and one positioned in the secondwaist region 38. Further, while the elastic waist feature 34 or any ofits constituent elements may comprise one or more separate elementsaffixed to the diaper 20, the elastic waist feature 34 may beconstructed as an extension of other elements of the diaper 20, such asthe backsheet 26, the topsheet 24, or both the backsheet 26 and thetopsheet 24. The elastic waist feature 34 may be constructed in a numberof different configurations including those described in U.S. Pat. No.4,515,595 issued to Kievit et al. on May 7, 1985; U.S. Pat. No.4,710,189 issued to Lash on Dec. 1, 1987; U.S. Pat. No. 5,151,092 issuedto Buell on Sep. 9, 1992; and U.S. Pat. No. 5,221,274 issued to Buell onJun. 22, 1993. Other suitable waist configurations may include waistcapfeatures such as those described in U.S. Pat. No. 5,026,364 issued toRobertson on Jun. 25, 1991 and U.S. Pat. No. 4,816,025 issued to Foremanon Mar. 28, 1989.

The diaper 20 may also include a fastening system 40. In particular,tape-type diapers have a fastening system. The fastening system 40preferably maintains the first waist region 36 and the second waistregion 38 in an overlapping configuration so as to provide tension aboutthe circumference of the waist opening of the diaper 20 to hold thediaper 20 on the wearer. The fastening system 40 preferably comprisestape tabs and/or hook and loop fastening components, although anyfastening means known in the art is generally acceptable.

In pant-type diapers, opposing sides, i.e., longitudinal edge portionsof first waist region 36 and second waist region 38, of the garment areseamed or welded to form a pant, as is known in the art. This allows thearticle to be used as a pull-on type diaper, such as a training pant.

The diaper 20 can also comprise side panels 30. The side panels 30 maybe elastic or extensible to provide a more comfortable and contouringfit by initially conformably fitting the diaper 20 to the wearer andsustaining this fit throughout the time of wear well past when thediaper 20 has been loaded with exudates since the elasticized sidepanels 30 allow the sides of the diaper 20 to expand and contract. Theside panels 30 may be constructed in any suitable configurations asknown in the art. Examples of diapers with elasticized side panels aredisclosed in U.S. Pat. No. 4,857,067, entitled Disposable Diaper HavingShirred Ears issued to Wood, et al. on Aug. 15, 1989; U.S. Pat. No.4,381,781 issued to Sciaraffa, et al. on May 3, 1983; U.S. Pat. No.4,938,753 issued to Van Gompel, et al. on Jul. 3, 1990; the hereinbefore referenced U.S. Pat. No. 5,151,092 issued to Buell on Sep. 9,1992; and U.S. Pat. No. 5,221,274 issued to Buell on Jun. 22, 1993; U.S.Pat. No. 5,669,897 issued to LaVon, et al. on Sep. 23, 1997 entitledAbsorbent Articles Providing Sustained Dynamic Fit; U.S. patentapplication Ser. No. 08/155,048 entitled Absorbent Article WithMulti-Directional Extensible Side Panels filed Nov. 19, 1993 in thenames of Robles, et al.

The diaper 20 preferably further includes leg cuffs 32 which provideimproved containment of liquids and other body exudates. Leg cuffs mayalso be referred to as legbands, side flaps, barrier cuffs, or elasticcuffs. U.S. Pat. No. 3,860,003 describes a disposable diaper whichprovides a contractible leg opening having a side flap and one or moreelastic members to provide an elasticized leg cuff (a gasketing cuff).U.S. Pat. Nos. 4,808,178 and 4,909,803 issued to Aziz et al. on Feb. 28,1989 and Mar. 20, 1990, respectively, describe disposable diapers having“stand-up” elasticized flaps (barrier cuffs) that improve thecontainment of the leg regions. U.S. Pat. Nos. 4,695,278 and 4,795,454issued to Lawson on Sep. 22, 1987 and to Dragoo on Jan. 3, 1989,respectively, describe disposable diapers having dual cuffs, includinggasketing cuffs and barrier cuffs. Barrier leg cuff elastics 29 may beused to improve containment of urine and other body exudates.

In the prior art, diapers' longitudinal edges 50 were left unfinished,that is, the edges of the component webs, such as the topsheet 24 andbacksheet 26, were left exposed. Although functional, this configurationleaves the diaper with an unfinished look. Attempts to make the diapermore garment-like by finishing the longitudinal edges 50 in aneconomical manner have thus far proved unsatisfactory. For example, theaddition of separate, discrete portions of edge-finishing materialsinvolves the cutting and accurate placement of materials on high-speedequipment which poses many difficult challenges and also increasesmaterial costs.

The method and apparatus of the present invention is directed to themaking of an improved diaper having a finished edge cuff. The finishededge cuff comprises an edge fold 60 that is formed around and/or along aportion of longitudinal edge 50. Edge fold 60 is formed by folding andseaming existing material (e.g., backsheet, topsheet, combinationbacksheet and topsheet, etc.) and does not require the addition of adiscrete part. Edge fold 60 can be extensible, and can be elastic orhighly elastic, or rendered elastic or highly elastic. Preferably, eachedge fold 60 has dimensions such that when the diaper 20 is worn, theedge fold 60 completely encircles the portion of longitudinal edge thatdefines the leg opening 25. The method and apparatus may also includethe additional steps/operations of activation, slitting and/or cutting.A variety of diaper designs and their corresponding methods ofmanufacture will now be discussed.

Referring first to FIGS. 2-8, non-limiting exemplary embodiments ofdiapers having finished edge folds 60 are shown. For illustrativepurposes, the method of manufacturing these exemplary diapers will bediscussed in an exemplary order of the steps being used. Additionally,some of the differences between each diaper within each step will alsobe discussed.

Activation

One step in preparing The chassis 22 for the subsequent creation of anedge fold 60 is “activation” (also referred to as incrementalstretching) of at least a portion of longitudinal edge 50. Incrementalstretching methods and suitable incrementally stretched materials aredescribed in commonly assigned U.S. Pat. No. 5,167,897 issued to Weberet al. on Dec. 1, 1992; U.S. Pat. application Ser. No. 09/897,823 andU.S. Pat. application Ser. No. 10/179,696. An activated or incrementallystretched laminate (e.g., laminate having an elastomeric materiallayered between two nonelastomeric materials) is formed with thenon-clastomeric material in a substantially relaxed, i.e., non-stretchedstate. The laminate is then incrementally stretched, resulting in thenonelastomeric material being strained beyond its elastic limit and inthe creation of plastically deformed areas of the non-elastomericmaterial, which areas generally remain laminated with the elastamericmaterial. In some embodiments, the laminate can be incrementallystretched to the elastic limit of the elastomeric material. In thefinished incrementally stretched laminate in a relaxed state, thecumulative hulk of the non-elastomeric material may be substantially nomore than tat of the original laminate prior to its being incrementallystretched. Thus, both the maximum elastic extension and the elasticextensibility of an incrementally stretched laminate may besignificantly greater than those of a conventionally gathered structure.Activation may be used to create stretch properties in the material.Activation may also be used to create high and low density portions inthe material, whereupon the contraction of incorporated elastics formssubstantially uniform gathers (“uniform” defined herein as having aspecific, repeatable or consistent appearance). In most instances, thepitch of the gathers is determined by the distance between the tips ofthe teeth on the activation tooling (see FIGS. 9-11). Various and variedpitch dimensions may be used so long as the gathers appear to besubstantially uniform.

Referring now to FIGS. 2 a-6 a (diapers 100, 200, 300, 400,respectively), a “multi-piece” chassis 22 (herein defined as a chassishaving attached side panels 30; in contrast to a “uni-body” chassishaving integral side panels and having a final shape determined by aside notch cut) is shown having at least a portion of longitudinal edge50 activated to strain and/or break fibers, said portion beingidentified as activated portion 63. In these exemplary embodiments,substantially the entire portion of the longitudinal edge 50 between theside panels 30 is activated. In this way, an edge fold 60 maysubstantially cover the entire circumference of the completed legopening 25. However, a smaller portion of longitudinal edge 50 may alsobe activated and still be appreciated within the present invention. InFIGS. 2 a-4 a, activated portion 63 is substantially linear. FIG. 5 ashows activated portion 63 being substantially arched and beginning fromthe longitudinal edge 50. FIG. 6 a shows activated portion 63 beingarched and not beginning from the longitudinal edge 50. Thesenon-limiting examples of activated portions 63 provide for a variety ofdifferent types of folding techniques which may ultimately lead to avariety of different shaped edge folds 60 (discussed infra).

Referring to FIGS. 7 a-8 a (diapers 600, 700, respectively), activatedportions 63 are created on a non-formed chassis (herein defined as achassis not yet having attached or defined side panels 30, e.g.,material web not yet cut or shaped). Activated portions 63 may be formedinboard to longitudinal edge 50 in an area which will later serve to bethe leg opening 25. Activated portions 63 may preferably be created inthe cross direction, wherein, the elongation of said activated portionsallows additional stretch in the machine direction.

FIG. 9 shows a first exemplary embodiment of activation apparatus 800that is capable of performing said activation process. A first roll 810having teeth 815 and a second roll 820 having teeth 825 engage to matewith one another. In this particular example, first roll 810 suppliesheat (e.g., conductive heat, radiant heat, convective heat, hot gas, hotair, etc.) through the lower base portion of teeth 815 within the radialregion 817. When a material 840 is fed in a direction indicated by arrow841 through said apparatus 800, material 840 is first exposed to saidheat and then to mating teeth 815, 825 to thus activate said material.

FIG. 10 shows a second exemplary embodiment of activation apparatus 900that is capable of performing said activation process. A first roll 910is capable of supplying heat in radial region 917. A second roll 920having teeth 925 and a third roll 930 having teeth 935 engage to matewith one another. When a material 940 is fed in a direction indicated byarrow 941 through said apparatus 900, material 940 is first exposed toheat via first roll 910 and then to mating teeth 925, 935 to thusactivate said material.

FIG. 11 shows an exemplary embodiment of a segment 811 of first roll 810having teeth 815. Heat is supplied through the underneath side ofsegment 811 through a distribution chamber 812 and then through holes813 positioned in between teeth 815.

Additional details and teachings of activation may be found in commonlyassigned U.S. Pat. Nos. 6,500,377; 5,167,897; 5,156,793; 5,143,679;5,527,304; 5,674,216; 5,628,741; 5,914,084; 6,114,263; 5,779,691;5,591,155, which are hereby incorporated by reference.

Cutting

In another step of forming edge fold 60, the activated chassis may becut. Said cutting step may be incorporated to assist in the subsequentfolding step in that the cut helps the longitudinal edge 50 fold ontothe chassis. For example, in FIG. 4 b, a simple cut 64 of minimal lengthis made substantially perpendicular to longitudinal edge 50. In anotherexample, FIG. 7 b, a simple cut 64 of moderate length is madesubstantially parallel to longitudinal edge 50. In yet another example,in FIGS. 6 b and 8 b, a more complex cut 64 is made which provides theshaping for leg opening 25. Additionally, trim 507 and trim 707 (i.e.,waste material) are removed. While cut 64 may be helpful, it is notrequired for subsequent folding, as exampled by the lack ofcorresponding “b” figures for FIGS. 2, 3 and 5 (i.e., FIGS. 2 b, 3 b and5 b do not exist).

Folding

In yet another step of forming edge fold 60, the activated chassis isfolded. Referring now to FIG. 2 c, a fold 66 is made over the entirelength of longitudinal edge 50. Said fold 66 may be made using a foldingboard or other known techniques. In this way, the side panels 30 arealso folded over. Fold 66 may be formed such that the leg elastic 31(also known as an outer cuff elastic) is now positioned in closeproximity to the newly-formed edge fold 60. After this fold step, theoriginal longitudinal edge 50 is moved inboard and is now identified asleading fold end 53. While only one leg elastic 31 is shown on each sideof chassis 22, one skilled in the art would appreciate that additionalleg elastics 31 may also be contemplated. When said leg elastics 31 areapplied to chassis 22, a multitude of affixing techniques may beutilized including, but not limited to, applying adhesive tosubstantially the entire length of leg elastic 31, applying adhesive tothe ends of leg elastic 31 (i.e., drawstring method; e.g., for curvedelastics in FIGS. 5 and 6), etc.

Referring now to FIGS. 3 c and 4 c, a fold 66 is made on a portion oflongitudinal edge 50 between side panels 30 by a folding rotary drum,for example, discussed infra, rather than by a folding board as in FIG.2. In this way, the side panels are not folded over. In comparing FIG. 3c to FIG. 4 c, it should be noted that because of cut 64 (see FIG. 4 b)the fold in FIG. 4 c is more tailored (i.e., contoured) than that ofFIG. 3 c (which was not previously cut), as depicted by the activatedportion 63 which extends beyond the leading fold end 53 in FIG. 3 c.

Referring now to FIGS. 5 c and 6 c, a fold 66 is made on a portion oflongitudinal edge 50 between side panels 30 such that said fold 66 issubstantially curved in shape to provide improved fit andleak-prevention benefits. In comparing FIG. 5 c to FIG. 6 c, it shouldbe noted that because of cut 64 (see FIG. 6 b) the fold in FIG. 6 c ismore tailored (i.e., contoured) than that of FIG. 5 c (which was notpreviously cut), as depicted by the positioning of leg elastic 31substantially along edge fold 60 in FIG. 6 c. While FIG. 6 c provides amore tailored fold, FIG. 5 c provides the unique advantage of providinga shaped diaper 20 that has a corresponding manufacturing process thatdoes not require cutting or trim removal.

Referring now to FIG. 7 c, a fold 66 is made inboard of longitudinaledge 50, more specifically, fold 66 is made in close proximity andsubstantially parallel to leg elastic 31. Because FIG. 7 c was nottrimmed to create leg openings 25, a final cutting/shaping willperformed later. Referring now to FIG. 8 c, a fold 66 is made on aportion of a new longitudinal edge 50′ between side panels 30. Thenotched-cut of FIG. 8B, allows the folding in FIG. 8 c to be moretailored (i.e., contoured) than that of FIG. 7, as depicted by theactivated portion 63 which extends beyond the leading fold end 53 inFIG. 7 c.

Referring now to FIGS. 12 a and 12 b, an exemplary embodiment of afolding rotary drum 1000 which is capable of high-speed folding isshown. Folding rotary drum 1000 has a drum surface 1005 and a flippingmechanism 1010. Flipping mechanism 1010 has a folding portion 1011 whichis not attached to drum surface 1005 and is supported in a rotatableposition by use of linkages that are operatively linked to cam follower1131. For example, primary linkage 1134 is operatively attached by asuitable pivot arm 1136 to the cam follower 1131, relative to an axis1020. Upon rotation of the drum 1000 around axis 1020, the cam follower1131 moves in a direction as indicated by arrow 1132. The radial motionof cam follower 1131 inwardly with respect to axis 1020, initiates thefolding motion of the folding portion 1011. More specifically, as thecam follower 1131 moves, linkage 1134 rotates belt drive 1138 to rotatein the direction as indicated by arrow 1139. Belt drive 1138 moves abelt 1140 which thereby turns at least one drive roller 1144, whichturns an associated linkage connector 1148, which itself is operativelyconnected to linkage 1152 which comprises a cooperating pair of linksthat are configured to facilitate a 180 degree fold-over motion offolding portion 1011. Other supporting links, shafts, bearings, and thelike, which are not necessarily shown, can be configured in known waysto complete this linkage. It may be preferable to design the belt drive1138 to have a diameter exactly twice the diameter of drive roller 1144,such that as belt drive 1138 rotates through an arc of 90 degrees, driveroller 1144 rotates through 180 degrees.

FIGS. 13 a-c show an exemplary progression of the folding step. Morespecifically, FIG. 13 a shows the longitudinal edge 50 being held byfolding portion 1011 in a pre-folded state. FIG. 13 b shows the foldingportion 1011 folding longitudinal edge 50 upward and onto backsheet 26to then create edge fold 60. FIG. 13 c shows the folding portion 1011releasing the newly-formed edge fold 60. Additional detail and teachingof similar folding apparatuses may be found in commonly assigned U.S.patent application Ser. No. 10/262,459, which is hereby incorporated byreference.

FIG. 14 shows an adaptation to folding apparatus 1000, wherein, thelinear folding portion 1011 is replaced with a curved folding member1011. Curved folding member 1011 is capable of making a non-linear edgefold 60 as exampled in FIGS. 5 and 6.

FIGS. 15 a and 15 b show schematic views of exemplary edge folds 60.More particularly, FIG. 15 a shows an edge fold 60, wherein, the fold ismade back onto the topsheet 24 (i.e., inside fold). FIG. 15 b shows anedge fold 60, wherein, the fold is made back onto the backsheet 26(i.e., outside fold). While both types of folds are acceptable, it maybe desirable to perform the inside fold because the terminal ends of thetop sheet 24 and backsheet 26 are not visible during wearing.

FIG. 15 c shows a schematic view of an exemplary edge fold 60, wherein,the backsheet 26 and barrier leg cuff 27 together are folded back ontothe barrier leg cuff 27. The chassis 22 in this particular example is amulti-piece chassis.

FIG. 15 d shows a schematic view of an exemplary edge fold 60, wherein,the backsheet 26 and barrier leg cuff 27 together are folded back ontothe barrier leg cuff 27. The chassis 22 in this particular example is auni-body chassis.

FIG. 15 e shows a schematic view of an exemplary edge fold 60, wherein,wherein, the backsheet 26 is folded onto itself as an inside fold. Thechassis 22 in this particular example is a multi-piece chassis, althougha uni-body chassis may also be contemplated.

FIG. 15 e shows a schematic view of an exemplary edge fold 60, wherein,wherein, the backsheet 26 is folded onto itself as an outside fold. Thechassis 22 in this particular example is a uni-body chassis, although amulti-piece chassis may also be contemplated.

Bonding

In yet another step of forming edge fold 60, the activated and foldedchassis is bonded. Bonding of the folded portion to the chassis may beaccomplished by application of adhesive, ultrasonic bonding, compressionbonding, thermal bonding, radio frequency bonding, infrared bonding,combinations thereof, and any other suitable bonding means known in theart which is appropriate for the specific materials employed. Referringto FIGS. 2 d-8 d, a bond 68 is shown and provided inboard to leg elastic31.

Order of Steps

FIG. 16 shows an exemplary schematic view of the folding manufacturingprocess for making the embodiment of FIG. 2, wherein, the steps ofactivation (in the machine direction), passive folding (e.g., by way ofa folding board) and bonding (e.g., by way of compression rolls) areused.

FIG. 17 shows an exemplary schematic view of the folding manufacturingprocess for making the embodiments of FIGS. 3 and 5, wherein, the stepsof activation (in the machine direction), active folding (e.g., by wayof a folding rotary drum 1000) and bonding (e.g., by way of compressionrolls) are used.

FIG. 18 shows an exemplary schematic view of the folding manufacturingprocess for making the embodiments of FIGS. 4 and 6-8, wherein, thesteps of activation (in the machine direction), cutting (e.g., by way ofdie cutting rolls to notch and/or shape), active folding (e.g., by wayof a folding rotary drum 1000) and bonding (e.g., by way of compressionrolls) are used.

While the order of the steps discussed herein were presented asactivating, cutting, folding and bonding, the present invention is notlimited to said order. For example, the activation step may be performedbefore or after the folding step, and before or after the bonding step.In fact, as discussed supra, the cutting step may even be eliminated.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention.

While particular embodiments of the present invention have beenillustrated and described, it would be apparent to those skilled in theart that various other combinations and modifications can be madewithout departing from the scope of the invention. It is thereforeintended to cover in the appended claims all such combinations andmodifications that are within the scope of this invention.

1. A method for making an edge fold on an absorbent article havinglongitudinal edges comprising the steps of: incrementally stretching aportion of the absorbent article to form an activated portion disposedlaterally inboard to and offset from a longitudinal edge of the article;cutting a portion of the absorbent article to form a cut disposedlaterally inboard to and substantially parallel to the longitudinaledge; folding at least a portion of the activated portion to form afolded portion with a folded portion length; and bonding the foldedportion along substantially all of the folded portion length to form anedge fold with substantially uniform gathers.
 2. The method of claim 1wherein the step of incremental stretching includes applying heat to theabsorbent article to assist in the incremental stretching.
 3. The methodof claim 2 further comprising applying heat to the absorbent articlebefore the step of incremental stretching to assist in the incrementalstretching.
 4. The method of claim 1 wherein the step of foldingincludes folding to form a substantially curved folded portion.
 5. Themethod of claim 1 wherein the step of incremental stretching includescreating substantially uniform gathers by using teeth tips on tooling.6. The method of claim 1 wherein the step of bonding is selected fromthe group including adhesive bonding, ultrasonic bonding, compressionbonding, thermal bonding, radio frequency bonding, infrared bonding andcombinations thereof.
 7. The method of claim 1 wherein the absorbentarticle is disposable.
 8. The method of claim 1 wherein the absorbentarticle is selected from the group including disposable diapers,sanitary napkins, pantiliners, incontinence briefs, and incontinenceundergarments.
 9. The method of claim 1 wherein the step of incrementalstretching includes incremental stretching a portion of the absorbentarticle which substantially extends between a pair of side panels toform the activated portion.
 10. The method of claim 1 wherein the stepof folding includes folding a portion of the absorbent article whichsubstantially extends between a pair of side panels to form theactivated portion.